Olfr78, a novel short‐chain fatty acid receptor, regulates glucose homeostasis and gut GLP‐1 secretion in mice

Abstract

Olfr78, which is a novel receptor for short‐chain fatty acid (SCFA) acetate and propionate, plays essential roles in some cellular processes. The present study aimed to investigate the role of olfr78 in regulating energy metabolism and delineate the underlying mechanisms using olfr78−/− mice. Deletion of olfr78 did not influence the adiposity of mice fed either normal chow or a high‐fat diet (HFD). However, olfr78−/− mice exhibited glucometabolic dysfunction, as evidenced by increased fasting blood glucose levels, decreased serum insulin levels, and impaired oral glucose tolerance under HFD feeding. When compared to wild‐type (WT) mice, olfr78 deficiency enhanced HFD‐induced gluconeogenesis and increased the mRNA expression of key gluconeogenic genes in the liver and kidney. Quantitative real‐time PCR results revealed that olfr78 expression was higher in the colon compared with other tissues in WT mice. Analysis of the gut microbiota in the feces of olfr78−/− mice using 16S rRNA gene sequencing revealed altered relative abundances of some representative SCFAs producers along with decreased levels of SCFAs, including propionic, isobutyric, 2‐methylbutyric, valeric, isovaleric, and 4‐methylvaleric acids. Importantly, mice lacking olfr78 had low circulating levels of glucagon‐like peptide 1 (GLP‐1). In the STC‐1 enteroendocrine cell line, propionate and acetate induced the secretion of the gut hormone GLP‐1, and this effect was partially abolished by olfr78 siRNA‐mediated knockdown. Together, these results suggest a previously undescribed, specific regulatory role for gut olfr78 in glucose homeostasis and highlight olfr78 as a potential target for diabetes treatment.

Exploring and comparing the anti‐obesity mechanisms of defatted rice bran total dietary fiber, insoluble dietary fiber, and soluble dietary fiber based on multi‐omics technologies

“…In contrast, a high-fat or low-fiber diet would promote the growth and proliferation of detrimental bacteria, accumulating toxins such as bacterial endotoxins and shiga toxins in the intestinal tract (Daien et al, 2017). With the intervention of DF, the levels of metabolites such as short-chain fatty acids (SCFAs) in the gut increased, which could enhance the stability of the intestinal barrier and facilitate intestinal immune function (Koh et al, 2016;Wang et al, 2023). Moreover, current research has revealed that SCFAs could penetrate the bloodstream to improve immunity and regulate glucolipid metabolism (Yang et al, 2020).…”